Preparation of starch and sulphuric acid



. 25' tin Patented May 15, 1923.

UNITED STATES PATENT OFFICE.

JOHN ALEXANDER LLOYD, F CQVENTRY, ENGLAND, ASSIGNOR TO COURTAULDS LIMITED, OF LONDON, ENGLAND.

PREPARATION OF STARCH AND SULPHURIC ACID.

No Drawing.

Be it known that I, Join ALEXANDER LLOYD, a subject of the 11in oi (lreat Britain, residing at lllUOliSlllQ, lridmore Road,

Coventry, England, have invented new and useful Improvements in the Preparation of Starch and Sulphuric Acid, of which the following is a specification.

This invention consists in an improved preparation of starch and sulphuric acid for use in setting baths eniplcyci'l in the manufacture of threads, lilamcnts. strips, or the like, from viscose as mentioned in the copendin application of M. T. Callimachi, Se'r. l\o. 548,477 filed herewith. patented March 27, 1923 under No. 1,449,380.

Then starch is mixed with fairly concentrated sul huric acid, containing say (30 per cent 11 88,, the starch, when added at the 'ordinary room temperature, gelatiniz'cs and forms lumps, which cannot, or only with great difficulty can, be mixed with the sulphuric acid, so as to yield a homogeneous mixture suitable for use in the aforesaid setbaths. ccordin'g to the present invention, this objection is overcome by employing the sul- ,phuric acid of a concentration of, or about from 50 to 65 per cent and atatemperatureoi from about 35 to about 15 centigrade, and adding the starch to such warm, or hot, sulphuric acid. In this way, the starch dis-' solves in the sulphuric acid and, in a moderately short time, depending to a large extent 85- on the temperature of the sul huric acid,'a solution is obtained suitable ting baths employed in the manufacture of artificial silk t reads, filaments, strips or the like, from viscose. The rate at which the starch can be added to the sulphuric acid varies according to the conditions under which the rocess is carried out Thus, for instance, whcna temperature of say 40 cen tigrade is chosen, the starch should be added; more slowly thanis necessary if a higher temperature, say '70" centigrade, be employed because, in this latter case, the starch dissolves more rapidly. Of course, if too high a temperature, or too concentrated sulto phuric acid were used, charring of the starch would be liable to occur, and the tem erature and the concentration of the su'lp uric acid should (be chosen with regard to thebut is capable of wide application.

or use in set- Application filed March 31, 1922. Serial No. 548,529.

product which it is desired to obtain. For instance. if a practically colourless solution be desired, a lower temperature should be employed than is necessary in cases where brown solutions can be produced and employed with impunity.

It was not to be foreseen that such raised temperatures can be employed, Without the sulphuric acid charring the starch and givin; a worthless product.

This invention is not limited to the employment of any ptll'tlClllfll lill'ld of starch, For in stance, maize starch, potato starch, and even ground rice, can be used. It is also not necessnr to employ the starch in a finely dividet condition, for instance, starch in the form of tapioca, as it is brought onto the market, can be employed.

The following examples will serve to illusirate how preparations can be prepared in accordance with this invention but the invention is not limited to the precise details of these examples. The parts are by weight.

Ema mple 1.

ll arm 116 parts of 52 per cent sulphuric acid to 40 centigrade and add thereto, gradually and whilst stirring, 56 parts of maize starch. The addition should extend over a eriod of about three and a half hours. ontinue stirring atthe same temperature for another two hours. The product then consists of a light, coloured solution of considerable mobility. Example 2. parts of 52 per cent sul Heat 116 huric acid to 70 centigrade and add gradual y and i 56 parts of maize starch. In

whilst stirring, this "case-the addition can be completed in about twenty minutes. Continue stirring for another ten minutes, whereupon a mo bile solution is obtained, which is however much darker in colour than is the product of the first example.

Ewample 3.

Heat 112 parts 'of per cent sul huric' acid to 57 centigrade and add gradual and whilst stirring, 56- artsof otato starch. The time required or the a dition in this case may be about thirty minutes. Then continue stirring at the same temporal um for about another thirty nnnuLes. \vlwt'mprm a light brown mobile liquul in obtained.

li'mmn-y le 4.

Raise (34 parts of per (Put sulphuric acid to'about 50 Centigrade unil ilK-ll llllfl. gradually and whilst Well stirring, 2 pulls of ground rice, the time ml-ton do big Slll'l'i addition being two and :1 quarter hours. Then continue stirring at ilw mun: l'c-mpm'nture for about sixteen hours A view lnown mobile solution is obtained.

E mam 717p .5,

Mix 72 parts of 27 per 00m mlpluurjw will with 168 parts of T7 per (out sulpluu'ur :uul. whereupon the iempolnlm'o of ilumixture rises to about 45 ovntigl'tulc. Then mill in the comm, of about P0 minutes while well .slii'i'iug 1m; rits of tapioca. Maintain the lvznpvmuu'c at ab ut 45 cuntigi'arlc. The iupiova gradually |'llHE-f ")l\'(3$, giving a ole-Lu lioinogem-ous sollllion.

Tln mutlioil of oidn ining :1 preparation for use in Siillllj; lmrlw for \iswoso. wlliuli coluprism tlw A'up oi lismlving starch in sulphuriu :wicl ol' mlwi'nmizilly from 5 lo 3 1m mul uonwnu'znion Hi :i lulupuraiulv oi' tsulxqnnliuliy iron: 3- ('1 H11 C.

ln rosiinmny law-mi l lnn'v signal] my 11mm in thin :qm'ili zllioii in tho pl'bsvnrbiof mosulm-l'ihing W1 1m )1 ll urn: r Saw nil-1s, l'l onlwi-z Jim ES Iluanz.

\MCR LLOYD,

Certificate of Correction.

It is hereby ccrtificd. (ha! in Lotte-rs Patent No. 1,455,630, granted May 15, 1923,

upon the application of John Alexander Lloyd, of Coventry, England, for an improvement in T114; Preparation of Starch and Sulphuric Acid, an error appears in the printm! spw-fivnti w I'Hgflh'illfl' r-m-roctinn as follows: Page 1, line 30. for 15 read 75" am] that. thrsaid Len-em ]"atent should be read with this correction therein that the 5mm). 11m v cunfnrm tot-11:: murd of the (use in the Patent fifiim.

Signed and sealed this 3m day of July, A. 1)., 1923.

[SI-EAL.) KARL FENNING,

Aai-ing (,"n-mmissioner of Patents. 

